THE reinstatement of Jonny Gray and Ross Ford has been a huge boost to the morale of the Scotland squad. Having had preparations for today’s Rugby World Cup quarter-final against Australia massively disrupted by the original three-week suspension of the two forwards, Vern Cotter must now decide whether bringing them into the match-day 23 or even the starting line-up will produce further disruption.

Yet whatever the head coach opts to do, whichever players take to the field at Twickenham, the size of the task awaiting the team will still be one of potentially intimidating magnitude. It is not merely a matter of playing their best match of the tournament so far - although they will have to do that by some way. Nor is it just a case of putting in their best performance since Vern Cotter took over as head coach, although they will have to do that too.

For Scotland to beat Australia today, they will have to play their best rugby of the century so far. It’s that difficult.

The 1999 team who won the last Five Nations Championship may be a distant memory by now - and not even a memory to the younger members of the team who will take on the Wallabies at Twickenham. But the type of relentless running rugby they played, and the irrepressible character they showed even when they lost by three points to England at today’s venue, is exactly what their present successors must emulate.

Scotland have pledged to take the game to Australia, or at least to try, but they will have to do so in as rational a manner as is possible amidst the mayhem of modern Test rugby. Samoa were able to throw caution to the wind last week because they had nothing to lose and their self-respect to rediscover, but there will have to be a measure of moderation about the attack today. Take calculated risks and they have a chance of getting some change out of the most parsimonious defence in the tournament. Embark on unthinking adventure and they will soon founder.

There is a very fine line between the two; one that cannot be precisely calibrated in the brain of every player. For some, such as Mark Bennett and Finn Russell, the natural urge to attack tends to overcome the inculcation of caution. For others, especially in the pack, a more conservative mindset will prevail.

If Scotland fall the wrong side of that line in either direction, they will suffer. They know that trying to close the game down is likely to do no more than limit the margin of defeat, and that becoming too gung ho could end up in them being blown away.

Above all - accepting that, no matter how well Scotland will attack, Australia will be able to bring their own offence into play - they will have to defend far more precisely than they were able to do last week. “We need to be a lot better defensively,” assistant coach Matt Taylor said yesterday. “Australia are exceptional in attack and have some really key individuals.

“We'll have to play our best. We'll have to execute well. We’ve got to do the things that we’ve done in practice.

“If you take the rankings, they’re second in the world and we’re ninth, so we’re looked on as a team that might find it difficult. But we’re looking forward to challenging them and putting on a good show.

“As a group we’re confident in our ability. We know we’ll have to play at our best to beat Australia, but it can motivate you when people write you off and think you can't do something.

“We’ve all been in teams where you’re the underdog and win. That’s happened many times, and on Sunday we’ll be seen as the underdog.

“We’re in the quarter-final of the World Cup and want to put our best foot forward. Australia have been the form team of the competition so far: you read a lot of the press and they’re one of the favourites to win it. We have to be right on top of our game. The guys are really enthusiastic and on top of the challenge and as coaches we’re looking forward to it as well.”

Taylor was speaking after morning training, and before news broke that Ford and Gray had been cleared. But even at that stage of the day he was convinced that the mood among the players was good.

“Our guys are really excited. We’ve trained really well just then in our session. I was really quite excited when we finished that session, because I felt it was one of the best sessions we've had in the whole time together.

“It's not always an indication, but it’s certainly a better feeling than when they don't play well. They were really connected, and played and executed well, so hopefully that's an accurate indication of how we’re going to play on Sunday.”

After a full week to build up to this, the biggest match of their careers so far for most of the squad, they may well not need any last-minute reminders of how to go about the task that awaits them. Still, asked what he would say to the squad as they left the dressing room to go on to the pitch, Taylor had a ready answer.

“Don't leave anything in the changing rooms. Put everything out there, because it's knockout rugby now. So you don't want to die wondering.”